// Tencent is pleased to support the open source community by making RapidJSON available.
//
// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip.
//
// Licensed under the MIT License (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// http://opensource.org/licenses/MIT
//
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.

#ifndef RAPIDJSON_INTERNAL_STRFUNC_H_
#define RAPIDJSON_INTERNAL_STRFUNC_H_

#include "../stream.h"
#include <cwchar>

RAPIDJSON_NAMESPACE_BEGIN
namespace internal
{

    //! Custom strlen() which works on different character types.
    /*! \tparam Ch Character type (e.g. char, wchar_t, short)
        \param s Null-terminated input string.
        \return Number of characters in the string.
        \note This has the same semantics as strlen(), the return value is not number of Unicode
       codepoints.
    */
    template <typename Ch> inline SizeType StrLen(const Ch* s)
    {
        RAPIDJSON_ASSERT(s != 0);
        const Ch* p = s;
        while (*p)
            ++p;
        return SizeType(p - s);
    }

    template <> inline SizeType StrLen(const char* s)
    {
        return SizeType(std::strlen(s));
    }

    template <> inline SizeType StrLen(const wchar_t* s)
    {
        return SizeType(std::wcslen(s));
    }

    //! Custom strcmpn() which works on different character types.
    /*! \tparam Ch Character type (e.g. char, wchar_t, short)
        \param s1 Null-terminated input string.
        \param s2 Null-terminated input string.
        \return 0 if equal
    */
    template <typename Ch> inline int StrCmp(const Ch* s1, const Ch* s2)
    {
        RAPIDJSON_ASSERT(s1 != 0);
        RAPIDJSON_ASSERT(s2 != 0);
        while (*s1 && (*s1 == *s2))
        {
            s1++;
            s2++;
        }
        return static_cast<unsigned>(*s1) < static_cast<unsigned>(*s2)
                   ? -1
                   : static_cast<unsigned>(*s1) > static_cast<unsigned>(*s2);
    }

    //! Returns number of code points in a encoded string.
    template <typename Encoding>
    bool CountStringCodePoint(const typename Encoding::Ch* s, SizeType length, SizeType* outCount)
    {
        RAPIDJSON_ASSERT(s != 0);
        RAPIDJSON_ASSERT(outCount != 0);
        GenericStringStream<Encoding> is(s);
        const typename Encoding::Ch*  end   = s + length;
        SizeType                      count = 0;
        while (is.src_ < end)
        {
            unsigned codepoint;
            if (!Encoding::Decode(is, &codepoint))
                return false;
            count++;
        }
        *outCount = count;
        return true;
    }

} // namespace internal
RAPIDJSON_NAMESPACE_END

#endif // RAPIDJSON_INTERNAL_STRFUNC_H_
